Aside from seeing the telethon hosted by Jerry Lewis on Labor
Day weekend, many people don't know much about muscular
dystrophy. Yet a quarter of a million kids and adults are living
with the disease, so chances are you may know someone who has
it.
What Is Muscular Dystrophy?
Muscular dystrophy (MD) is a
genetic disorder
that weakens the muscles that help the body move. People with MD
have incorrect or missing information in their genes, which
prevents them from making the proteins they need for healthy
muscles
. Because MD is genetic, people are born with the problem -
it's not contagious and you can't catch it from someone who
has it.
MD weakens muscles over time, so children, teens, and adults who
have the disease can gradually lose the ability to do the things
most people take for granted, like walking or sitting up.
Someone with MD might start having muscle problems as a baby or
their symptoms might start later. Some people even develop MD as
adults.
Several major forms of muscular dystrophy can affect teens, each
of which weakens different muscle groups in various ways:
-
Duchenne
(pronounced: due-
shen
)
muscular dystrophy
(DMD)
, the most common type of the disease, is caused by a problem
with the gene that makes a protein called
dystrophin
. This protein helps muscle cells keep their shape and strength.
Without it, muscles break down and a person gradually becomes
weaker. DMD affects boys. Symptoms usually start between ages 2
and 6. By age 10 or 12, kids with DMD often need to use a
wheelchair. The heart may also be affected, and people with DMD
need to be followed closely by a lung and heart specialist. They
can also develop
scoliosis
(curvature of the spine) and tightness in their joints.
Over time, even the muscles that control breathing get weaker,
and a person might need a ventilator to breathe. People with DMD
usually do not survive beyond their late teens or early
adulthood.
-
Becker muscular dystrophy (BMD)
, like DMD, affects boys. The disease is very similar to DMD, but
its symptoms may start later and can be less severe. With BMD,
symptoms like muscle breakdown and weakness sometimes don't
begin until age 10 or even in adulthood. People with BMD can also
have breathing, heart, bone, muscle, and joint problems. Many
people with BMD can live long, active lives without using a
wheelchair. How long a person with BMD can live varies depending
on the severity of any breathing and heart problems.
-
Emery-Dreifuss
(pronounced:
em
-uh-ree
dry
-fuss)
muscular dystrophy
(EDMD)
typically starts causing symptoms in late childhood to early
teens and sometimes as late as age 25. EDMD is another form of
muscular dystrophy that affects mostly boys. It involves muscles
in the shoulders, upper arms, and shins, and it often causes
joint problems (joints can become tighter in people with EDMD).
The heart muscle may also be affected.
-
Limb-girdle muscular dystrophy
(LGMD)
affects boys and girls equally, weakening muscles in the
shoulders and upper arms and around the hips and thighs. LGMD can
begin as early as childhood or as late as mid-adulthood, and it
often progresses slowly. Over time, a wheelchair might be
necessary to get around. There are many different types of LGMD,
each with its own specific features.
-
Facioscapulohumeral
(pronounced:
fa
-she-o-
skap
-you-lo-
hyoo
-meh-rul)
muscular dystrophy (FSHD)
can affect both guys and girls, and it usually begins during the
teens or early adulthood. FSHD affects muscles in the face and
shoulders and sometimes causes weakness in the lower legs. People
with this type of MD might have trouble raising their arms,
whistling, or tightly closing their eyes. How much a person with
this form of muscular dystrophy is affected by the condition
varies from person to person. It can be quite mild in some
people.
-
Myotonic
(pronounced:
my
-uh-
tah
-nick)
dystrophy (MMD)
is a form of muscular dystrophy in which the muscles have
difficulty relaxing. In teens, it can cause a number of problems,
including muscle weakness and wasting (where the muscles shrink
over time), cataracts, and heart problems.
-
Congenital muscular dystrophy (CMD)
is the term for all types of MD that show signs in babies and
young children, although the MD isn't always diagnosed right
away. Like other forms of MD, CMD involves muscle weakness and
poor muscle tone. Occurring in both girls and boys, it can have
different symptoms. It varies in how severely it affects people
and how quickly or slowly it worsens. In rare cases, CMD can
cause learning disabilities or mental retardation.
The life expectancy (in other words, how long a person may live)
for many of these forms of muscular dystrophy depends on the degree
to which a person's muscles are weakened as well as how much
the heart and lungs are affected.
How Do Doctors Diagnose MD?
In addition to doing a physical examination, the doctor will ask
you about any concerns and symptoms you have, your past health,
your family's health, any medications you're taking, any
allergies you may have, and other issues. This is called the
medical history
.
Tests can help the doctor determine which type of MD a person
has and rule out other diseases that affect the muscles or nerves.
Some tests measure how nerves and muscles are working. Others check
the blood for levels of certain
enzymes
, the proteins that cause chemical changes like converting food to
energy. Abnormally high blood levels of certain enzymes from muscle
cells are present in many people with MD.
Sometimes a
muscle biopsy
is needed. The doctor removes a small piece of muscle tissue and
examines it under a microscope. If a person has MD, the muscle
tissue will have some unusually large fibers, and some of the other
fibers will show signs of breaking down. Finally, genetic testing
can show if a person has Duchenne MD.
How Is MD Treated?
There is no cure for MD, but doctors and scientists are working
hard to find one. Some scientists are trying to fix the defective
genes that lead to MD so they will make the right proteins. Others
are trying to make chemicals that will act like these proteins in
the body. They hope that this will help the muscles to work
properly in people with MD. Doctors are also dedicated to finding
the best ways to treat the symptoms of MD so that kids, teens, and
adults with the disease can live as comfortably and happily as
possible.
Teens with MD can do some things to help their muscles. Certain
exercises and physical therapy can help them avoid
contractures
, a stiffening of the muscles near the joints that can make it
harder to move and can lock the joints in painful positions. Often,
teens are fitted with special braces to ensure flexible joints and
tendons
(the strong, rubber band-like tissues that attach muscles to
bones). Surgery is sometimes used to reduce pain and increase
movement from contractures.
Because we rely on certain muscles to breathe, some teens with
MD need respiratory aids, such as a ventilator, to help them
breathe. Teens with MD also might need to be treated for problems
like scoliosis, which can be caused by weakened muscles or muscles
that are contracting or pulling too tightly.
For some types of MD, medication can help. Guys with Duchenne MD
may be helped by a medicine called prednisone, and teens with
myotonic MD might use phenytoin or quinine to relax muscles.
It's also important that people with heart
problems caused by muscular dystrophy be monitored by a heart
specialist.
What's It Like for Teens With MD?
Teens have different experiences depending on the type of MD.
One person might have weakened shoulder muscles and not be able to
raise a hand in class. Someone might be unable to smile because of
weak facial muscles. Another person might have weak muscles in the
pelvis or legs, making it hard to walk from class to class. In some
cases, you might not even be able to tell that a teen has MD.
For teens with MD, it can be hard to come to terms with the
disease, especially because it gradually gets worse. For example,
when someone who walks to class must start using a wheelchair in
school, it can be a difficult adjustment. Support from doctors,
family, and friends can make it easier to deal with MD. Changes
like wider doorways at home and school can make it easier for teens
with MD to do many of the things they enjoy.
If you know someone who has MD, there's a lot you can do to
offer help and support. For example, some people with MD may need
help getting books out during class or rides to and from
events.
Often, people with illnesses that gradually get worse over time
can start to feel cut off from friends, especially as their friends
may be going out and doing more things while they feel like
they're becoming more housebound. Try planning activities that
include a friend, brother, or sister with MD, such as playing video
games or watching movies at his or her home. Your friend or sibling
will always be the same person - just more limited in movement.
Reviewed by:
Alisa Clark, MSN, RN
Date reviewed: January 2007
Originally reviewed by:
Mena T. Scavina, DO
Note: All information is for educational purposes only. For specific medical advice,
diagnoses, and treatment, consult your doctor.
© 1995-2009 The Nemours Foundation/KidsHealth. All rights reserved.